House investigators pressed outgoing Environmental Protection Agency (EPA) Administrator Lisa Jackson, in a letter noting criminal penalties for hiding federal records, to reveal all of the email accounts that she and agency employees use to conduct official business.

Jackson is receiving the letter just days after the EPA had to release, because of court order, 2,100 emails associated with an email account registered in the name of “Richard Windsor,” which was actually an alias used by Jackson.

“The use of an alias account to conduct official Agency business makes compliance with the [Federal Records Act] and [Presidential Records Act] more difficult because the alias may not be matched to an actual Agency employe,” House Oversight and Government Reform Committee chairman Darrell Issa, R-Calif., wrote in the Wednesday letter, which was obtained exclusively by The Washington Examiner.

“The use of an alias email account to conduct government business also creates difficulties in fulfilling the FOIA or litigation requests. Furthermore, conducting official business using an alias may implicate criminal or civil penalties for the unlawful concealment of federal records,” Issa added. The committee asked for a response by January 29th.

The House Energy and Commerce Committee has also written the agency about the secret email account, while the EPA inspector general has begun an investigation.